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Psyche 8:243-246, 1897.

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PSYCHE.
A PROBLEM IN DISTRIBUTION.
BY VERNON L. KELLOGG, STANFORD UNIVERSITY, CALIFORNIA, In a systematic* paper on North
American Mallophaga, published in
1896,I briefly outlined a "problem in
distribution " (pp. 48-57 of the paper
referred to) which seemed to me at that
time a very suggestive problem, indeed,
but which had a slightly uncertain note
in its assumption of certain foundation
facts. These assumed conditions had,
truly, all the seeming of facts, but there failed a possible absolute verification of them. A recent trip to Europe has
given me opportunity to examine (by
the kindness of Prof. Otto Taschenberg
of the University of Halle) a sufficient number of type and authentically deter-
mined specimens of European Mallo-
phaga to supply the needed verification
of my earlier assumptions, and to dis-
cover further new and equally interest-
ing incidents of the problem,
The problem, summarily stated, is
this: The species of the Mallophaga
(which are wingless, free-living, external parasites on birds and mammals) are,
in a majority of cases, peculiar each to some one host species. But the instan-
*New Mrilophaga I (Contributions to Biology from the Hopkina Seaside Laboratory, (VI 1806.
ces are many in which this condition of
distribution does not obtain, but where
a single parasite species is common to a few, or to even many, host species.
How does this latter condition come to
exist ?
As the Mallophaga are wingless their
power of migration from bird to bird is
evidently limited. They run strongly
and quickly, but they can live for only
a comparatively short time off the body
of the warm-blooded host, or on its cold dead body. After a bird is shot the
Mallophaga on it die in from two hours
to three or four days; in infrequent
instances I have found them alive on
the drying skin of the host at the end of a week or ten days, Very rarely, indeed, have I found Mallophaga under natural
conditions off of the body of the host.
Accounts have been given of finding
chicken lice " on the roosts in chicken
houses, a quite possible occurrence.
But even in such a likely place as an
ocean rock from which I had just
frightened hundreds of pelicans, como-
rants and gulls have I looked vainly for Matlophaga which might be wandering
from host to host.




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244 PSYCHE. [August 1898.
Wherever actual contact occurs be-
tween the bodies of the hosts, however,
migration can and evidently does take
place. In this way is the parasite
species perpetuated on its normal host
species; the parasites can migrate from
male to female, and vice versa, during
copulation, and from parents to young
in the nesting season. But instances of
contact among other individuals of the
same host species and even among indi-
viduals of different host species are not only possible but in the case of certain birds are probably frequent. Wherever
such contact occurs no further explana-
tion of the occurrence of single parasite species common to two or more host
species is necessary. There is also a
possible explanation of possible rare
cases of commonness of parasite species
to two or more host species whose indi-
viduals apparently never come in contact. Sharp * has recorded a case in which a
Hippoboscid (winged Dipterous parasite
of birds) which was captured while fly-
ing " was found to have some Mallo-
phaga attached to it." Such instances
must be rare.
It will be of interest now to note the
various kinds of cases (for the cases are fairly amenable to classifying) in which a parasite species is common to two or
more host species. I have taken Dm-
pJw~us l+ from thirteen species of gulls (twelve species of Larus and one of
Rissa), and Ninnus Hneolaius from nine
'Sharp, D., Proceedings entomological society of London ,800, p. xxx.
species of gulls (all Larus).
The gulls
are gregarious in habit, roosting together in great numbers on ocean rocks. Un-
doubtedly there is frequent absolute
contact of the bodies of individuals of
various species, giving opportunity for
actual migration. But together with the
gulls on the ocean rocks sit other mari- time birds; for example, on Scotland's
famous Bass Rock Sda h m a (a gan-
net), Aka troile (an auk), and Kissa
tridactyla (a gull) breed socially together (see the striking wall-case of Bass Rock birds in the Natural History Museum,
Kensington, London). On the "bird
rocks " off Monterey, California, I have found cormorants, pelicans and gulls
roosting together, and have found Lifieu- YUS toxoceras, a long known parasite of
the cormorants, on a pelican (PeZ.eca?zus caUfornicus) , as well as on the cormorants (Pha/acromrax diZ.ofhus albociliatus) .
Actual migration of the parasites from
the captured prey to the raptorial cap-
turer may evidently take place; I have
found a fhysostornum (genus normally
limited to passerine birds) on a sparrow hawk. It is conceivable that among
birds with whom hybridization is not
infrequent a parasite species may
become common to several hosts.
Thus the hybridizing which is notorious
among allied duck species may help
account for the fact that Doco~honi-s
zc/e?+odes is common to many cluck
species (I have taken il from nine) and
that Trinotmt luridurn is similarly com- mon to many hosts (I have taken it also
on nine duck species).




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August 1898.1 PSYCHE. 245
But the commonness of a parasite
species to several host species occurs
in cases where it seems impossible to
assume an actual migration. The hawks
have two or three parasites, as Docofho- rus flatysto- which are common to
several of them; Docophorus cursor is
common to several owl species, Doco-
phorus excisus to several swallows, Doco- phorus californiensis to several wood-
peckers, and Docophorus cornmunis ('with its so-called varieties) to a great many passerine birds. The other genera of
Mallophaga present many similar cases.
Now in all of the cases mentioned, and
it is true of practically all of them
unmentioned, it will be noted that the
common hosts are closely allied forms,
i. e., different species of a single genus, or, and not infrequently, different but
allied genera. Only in the case of
Docophoi-iis communis do we have a para- site's range extending over family limits, the hosts of this form representing sev- eral passerine families.
While actual migration in the just-
mentioned cases is almost an impossible
condition, there are other cases to which I shall now refer in which the possi-
bility of actual migration is positively precluded. These cases are those in
which a parasite species is common to
both American and European hosts
of different species and of habits and
geographical range which absolutely
preclude the possibility of the migration of the parasites from one host species
to the other. A few details as to these
cases should be of interest. Two hun-
dred and sixty-two * species of hfallo-
phaga have been taken from birds of
North America. Of these 262 species,
157 are new species while the remain-
ing 105 species are assumed to be
specifically identical with Mallophaga
originally described from European (or
Asiatic) birds. In a dozen or more
cases the American forms are called
varieties of the foreign species. The
determinations of the American speci-
mens, referred to European species,
were based on the descriptions and
figures of the European authors Nitzsch, Giebel, Denny, Piaget, Taschenberg, et
al. In the case of Piaget and Taschen-
berg, especially, these descriptions are detailed and excellent, and the figures
good. There existed, however, a doubt
in these determinations. As already
mentioned, I have recently had oppor-
tunity to examine many European speci-
mens in the collections of the University of Halle, and to compare with them
American specimens taken with me for
the purpose of this study. This com-
parison leaves no question as to the
specific identity of American and Euro-
pean specimens taken from different
host species. I could not make this
comparison for all of the 105 species
presumably identical, but could do it for *The records of the occurrence of these species art included in ProfessorOsbom'spapers, notably his " Insects Affecting Domestic Animals," Bull. no. 5, ns., Div. of Ent., U. S. Dep't. A&., 1896, and in my New Mallo- pliafl, I. dm, New Mallophaga, 11, (i8g6), and New Mallophaga, 111, (now printing).
A very few records are
included in the works of European authors. The number given, 262, is subject to correction, due to a few it~stances of duplication in Professor Osbarn's and my papers.



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246 PSYCHE. [~ugust 1898.
many of them, and in all of the cases
studied the identity is apparent.*
To consider now the problem of how
this condition comes to exist we may
first refer to and put out of the way the few cases of the common occurrence of^
a bird species on the two continents,
as in the case of imported species
(domestic fowl, song-birds, the English
Sparrow), or in the case of species of
circumpolar range. We may take into
account, also, the remote possibility of the ' meeting on mid-ocean islands of
American and European maritime birds
of different species. Eliminating these
few explicable instances of the common-
ness of parasite to the two continents,
we have left the great bulk of cases to
explain in some way which
does not
presuppose an actual migration from
European to American host.
Now it is to be noted that the several
host species to which a parasite species is common are almost always closely
allied forms, that is, species of the
same genus or representatives of two
closely allied genera. For examples,
Docophoruspe~tusus described by Nitzsch
from Fulica &a, the European coot, I
have taken from Frdica americana, the
American coot ; Docophorus latifrom
described by Nitzsch from Cumins cam-
rus I have taken from Coccyzns califir-
niczis occidc?ztaZis ; Nirmus fuscoma.ryina.fus found in Europe on Podiceps I have
found in America on Colymbus ; fVirn1z6s Indeed, I have made new species out of one or two American forms which should evidently be referred to already known European species.
piceus from the European avocet, Recur-
virostra avocetta, is found in America on the American avocet, Keczi/~irosfra
mnericma ; Lipeurus ferox, recorded
from two European species of Diomedea
I have taken from Diomedea albatrus
(California) ; Lipeurus forficu/atus de- scribed by Nitzsch from Pelecanus
onowotalus I have taken from Pelecamis
eryth~~orhyncftus (Kansas) and P. cali-
fornicns (California). And so on through the seventeen or eighteen other genera
of Mallophaga. There are a few in-
stances, it must be said, in which the
relationship of hosts is not so close,
the always conspicuous example of this
condition being the occurrence of JDoco- phorns comfminis through several families of passerine birds. But it may be said
almost without qualification that where
a parasite species found in Europe has
also been found in America its American
hosts are the American species repre-
senting the European genus, or belong
to a genus very closely allied to the
European one. On this fact I base my
belief that the occurrence of a parasite species common to several hosts under
circumstances which do not admit of
the migration of the parasites from birds to bird is due to the persistence of the parasite species unchanged from the
common ancestor of the two or more
now distinct but closely allied bird
species. With the spreading of the
ancestral species, geographical races
have arisen within the limits of the
species which have with time and with
isolation, caused by newly appearing




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August 18q8.1
PSYCHE.
geographical barriers due to geologic
or climatic changes, come to be distinct species - species often distinguished
only by superficial differences in color and markings of plumage, etc.
The par-
asites have remained practically unaf-
fected by the conditions which have
produced the differences among the
birds; the temperature of the host's
body, the feathers as food, all of the
environment of the parasite is practically unchanged. The parasitic species thus
remains unchanged, while the ancestral
Larus or Anas species becomes differ-
entiated into a dozen or score of specific forms, all with a common parasite.
If
this proposed solution of the problem
may he accepted, it introduces a factor
into problems of distribution, where
parasites are concerned, which I do not
recall having seen presented before.
NOTES ON NEW ENGLAND ACRIDIIDAE, IV,-ACRIDIINAE, I. BY ALBERT P. MORSE, WELLESLEY, MASS.
The New England species of Acridii-
nae or spine-breasted locusts are readily recognized by the presence of a promi-
nent spine or tubercle projecting from
the prosternuin between the bases of the anterior pair of legs. Sixteen species
of this sub-family have been taken in
New England; one of these, however,
Schistocerca americana, being of purely
adventitious occurrence. Those that
form the fauna proper to the district
fall into two groups: two species of
Schistocerca, and thirteen species of
Melanopli. The former genus is at
present undergoing revision by Mr.
Scudder; the latter group forms the
subject of his monumental "Revision of
the Melanopli" (Proc. U. S. Nat. Mus.,
vol. xx, pp. 1-42 I) to which the student is referred for a general discussion of
the group, for systematic characters,
and information concerning its extra-
limitally.
I have adopted here the sequence of
genera and species given in that work,
preceded by Schistocerca, as follows :
Schistocerca (3 sp.), Hesperotettix (I
sp.), Podisma (I sp.), Melanoplus (10
sp., in this order,- attains, sciidderi, mancus, fasciatus,femur-rulirum, exfrem- us minor, collinus, femoyatus, punctula- fns) , and finally, Paroxya (I sp.) . The student dealing with specimens from
New England or the northeastern States
alone, however, will find a different ar- rangement of his collection preferable,
e. g., the following :- Schistocerca (3
sp.), Paroxya, Hesperotettix, and Podis- ma (each monotypic in New England),
and finally Melanoplus, in this order :
mancus, swdderi, athis, femur-rztbriim,
exfrtmus, fasciatus, minor, collinus, punt-



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